Groundwater Contamination

water pollution

water pollution, contamination of water resources by harmful wastes; see also sewerage, water supply, pollution, and environmentalism.

Industrial Pollution

In the United States industry is the greatest source of pollution, accounting for more than half the volume of all water pollution and for the most deadly pollutants. Some 370,000 manufacturing facilities use huge quantities of freshwater to carry away wastes of many kinds. The waste-bearing water, or effluent, is discharged into streams, lakes, or oceans, which in turn disperse the polluting substances. In its National Water Quality Inventory, reported to Congress in 1996, the U.S. Environmental Protection Agency concluded that approximately 40% of the nation's surveyed lakes, rivers, and estuaries were too polluted for such basic uses as drinking supply, fishing, and swimming. The pollutants include grit, asbestos, phosphates and nitrates, mercury, lead, caustic soda and other sodium compounds, sulfur and sulfuric acid, oils, and petrochemicals.

In addition, numerous manufacturing plants pour off undiluted corrosives, poisons, and other noxious byproducts. The construction industry discharges slurries of gypsum, cement, abrasives, metals, and poisonous solvents. Another pervasive group of contaminants entering food chains is the polychlorinated biphenyl (PCB) compounds, components of lubricants, plastic wrappers, and adhesives. In yet another instance of pollution, hot water discharged by factories and power plants causes so-called thermal pollution by increasing water temperatures. Such increases change the level of oxygen dissolved in a body of water, thereby disrupting the water's ecological balance, killing off some plant and animal species while encouraging the overgrowth of others.

Other Sources of Water Pollution

Towns and municipalities are also major sources of water pollution. In many public water systems, pollution exceeds safe levels. One reason for this is that much groundwater has been contaminated by wastes pumped underground for disposal or by seepage from surface water. When contamination reaches underground water tables, it is difficult to correct and spreads over wide areas. In addition, many U.S. communities discharge untreated or only partially treated sewage into the waterways, threatening the health of their own and neighboring populations.

Along with domestic wastes, sewage carries industrial contaminants and a growing tonnage of paper and plastic refuse (see solid waste). Although thorough sewage treatment would destroy most disease-causing bacteria, the problem of the spread of viruses and viral illness remains. Additionally, most sewage treatment does not remove phosphorus compounds, contributed principally by detergents, which cause eutrophication of lakes and ponds. Excreted drugs and household chemicals also are not removed by present municipal treatment facilites, and can be recycled into the drinking water supply.

Rain drainage is another major polluting agent because it carries such substances as highway debris (including oil and chemicals from automobile exhausts), sediments from highway and building construction, and acids and radioactive wastes from mining operations into freshwater systems as well as into the ocean. Also transported by rain runoff and by irrigation return-flow are animal wastes from farms and feedlots, a widespread source of pollutants impairing rivers and streams, groundwater, and even some coastal waters. Antibiotics, hormones, and other chemicals used to raise livestock are components of such animal wastes. Pesticide and fertilizer residues from farms also contribute to water pollution via rain drainage.

Ocean Pollution

Large and small craft significantly pollute both inland and coastal waters by dumping their untreated sewage. Oil spilled accidentally or flushed from tankers and offshore rigs (900,000 metric tons annually) sullies beaches and smothers bird, fish, and plant life. In 1978 in one of the world's worst single instances of water pollution, the Amoco Cadiz broke in two on the coast of Brittany, France, and spilled 1.6 million barrels of oil, causing great environmental destruction. Oil well blowouts during offshore drilling, such as the 1979 Ixtoc 1 blowout in Gulf of Mexico off Mexico and the 2010 Deepwater Horizon blowout in the Gulf of Mexico off Louisiana, have also caused severe oil pollution. In addition to its direct damage to wildlife, oil takes up fat-soluble poisons like DDT, allowing them to be concentrated in organisms that ingest the oil-contaminated water; thus such poisons enter the food chains leading to sea mammals and people (see ecology).

Both DDT, which has been banned in the United States since 1972, and PCBs are manufactured in many parts of the world and are now widespread in the Atlantic and Pacific oceans. In addition, tarry oil residues are encountered throughout the Atlantic, as are styrofoam and other plastic rubbish. Plastic bits litter sections of the Pacific and Atlantic, accumulating in greater concentrations to form "garbage patches" where the currents are slack. Garbage, solid industrial wastes, and sludge formed in sewage treatment, all commonly dumped into oceans, are other marine pollutants found worldwide, especially along coastal areas.

Dangers of Water Pollution

Virtually all water pollutants are hazardous to humans as well as lesser species; sodium is implicated in cardiovascular disease, nitrates in blood disorders. Mercury and lead can cause nervous disorders. Some contaminants are carcinogens. DDT is toxic to humans and can alter chromosomes. PCBs cause liver and nerve damage, skin eruptions, vomiting, fever, diarrhea, and fetal abnormalities. Along many shores, shellfish can no longer be taken because of contamination by DDT, sewage, or industrial wastes.

Dysentery, salmonellosis, cryptosporidium, and hepatitis are among the maladies transmitted by sewage in drinking and bathing water. In the United States, beaches along both coasts, riverbanks, and lake shores have been ruined for bathers by industrial wastes, municipal sewage, and medical waste. Water pollution is an even greater problem in the Third World, where millions of people obtain water for drinking and sanitation from unprotected streams and ponds that are contaminated with human waste. This type of contamination has been estimated to cause more than 3 million deaths annually from diarrhea in Third World countries, most of them children.

Legislation and Control

The United States has enacted extensive federal legislation to fight water pollution. Laws include the Federal Water Pollution Control Act (1948), the Clean Water Act (1972), the Marine Protection, Research, and Sanctuaries Act (1972), the Safe Drinking Water Act (1974), and the Federal Insecticide, Fungicide, and Rodenticide Act, as amended in 1988. International cooperation is being promoted by the Inter-Governmental Maritime Consultive Organization (IMCO), a UN agency. Limitation of ocean dumping was proposed at the 80-nation London Conference of 1972, and in the same year 12 European nations meeting in Oslo adopted rules to regulate dumping in the North Atlantic. An international ban on ocean dumping in 1988 set further restrictions.

The Columbia Encyclopedia, 6th ed. Copyright© 2013, The Columbia University Press.

Selected full-text books and articles on this topic

Groundwater Contamination in the United States
Ruth Patrick; Emily Ford; John Quarles; Veronica I. Pye; Ruth Patrick; John Quarles.
University of Pennsylvania Press, 1987 (2nd edition)
Demanding Clean Food and Water: The Fight for a Basic Human Right
Joan Goldstein.
Plenum Press, 1990
Librarian’s tip: "Groundwater: The Forgotten Child of Nature" begins on p. 110
Measuring the Benefits of Clean Air and Water
Allen V. Kneese.
Resources for the Future, 1984
Librarian’s tip: Chap. 11 "Emerging Areas for Benefit Estimation: Visibility, Acid Rain, and Groundwater Contamination"
Borrowed Earth, Borrowed Time: Healing America's Chemical Wounds
Glenn E. Schweitzer.
Plenum Press, 1991
Librarian’s tip: "Protecting Our Groundwater Resources" begins on p. 159
Groundwater Arsenic Contamination in Bangladesh and West Bengal, India
Chowdhury, Uttam K.; Biswas, Bhajan K.; Chowdhury, Tarit Roy; Samanta, Gautam; Mandal, Badal K.; Basu, Gautam C.; Chanda, Chitta R.; Lodh, Dilip; Saha, Khitish C.; Mukherjee, Subhas K.; Roy, Sibtosh; Kabir, Saiful; Quamruzzaman, Quazi; Chakraborti, Dipankar.
Environmental Health Perspectives, Vol. 108, No. 5, May 2000
Arsenic Groundwater Contamination in Middle Ganga Plain, Bihar, India: A Future Danger?
Chakraborti, Dipankar; Mukherjee, Subhash C.; Pati, Shyamapada; Sengupta, Mrinal K.; Rahman, Mohammad M.; Chowdhury, Uttam K.; Lodh, Dilip; Chanda, Chitta R.; Chakraborti, Anil K.; Basu, Gautam K.
Environmental Health Perspectives, Vol. 111, No. 9, July 2003
Industrial Topography, Groundwater, and the Contours of Environmental Knowledge
Colten, Craig E.
The Geographical Review, Vol. 88, No. 2, April 1998
You Can't Eat GNP: Economics as If Ecology Mattered
Eric A. Davidson.
Perseus Publishing, 2000
Librarian’s tip: "Groundwater Pollution and Depletion: The Insidious Externality" begins on p. 124
Groundwater Problems Caused by Irrigation with Sewage Effluent
Bouwer, Herman.
Journal of Environmental Health, Vol. 63, No. 3, October-September 2000
Is Contaminated Groundwater an Important Cause of Viral Gastroenteritis in the United States? (Features)
Frost, Floyd J.; Kunde, Twila R.; Craun, Gunther F.
Journal of Environmental Health, Vol. 65, No. 3, October 2002
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